feat(Anthropic Chat Model Node): Fetch models dynamically & support thinking (#13543)

packages/@n8n/nodes-langchain/nodes/llms/LMChatAnthropic/LmChatAnthropic.node.ts

@@ -14,6 +14,7 @@ import {
 
 import { getConnectionHintNoticeField } from '@utils/sharedFields';
 
+import { searchModels } from './methods/searchModels';
 import { makeN8nLlmFailedAttemptHandler } from '../n8nLlmFailedAttemptHandler';
 import { N8nLlmTracing } from '../N8nLlmTracing';
 
@@ -69,15 +70,23 @@ const modelField: INodeProperties = {
 	default: 'claude-2',
 };
 
+const MIN_THINKING_BUDGET = 1024;
+const DEFAULT_MAX_TOKENS = 4096;
 export class LmChatAnthropic implements INodeType {
+	methods = {
+		listSearch: {
+			searchModels,
+		},
+	};
+
 	description: INodeTypeDescription = {
 		displayName: 'Anthropic Chat Model',
 		// eslint-disable-next-line n8n-nodes-base/node-class-description-name-miscased
 		name: 'lmChatAnthropic',
 		icon: 'file:anthropic.svg',
 		group: ['transform'],
-		version: [1, 1.1, 1.2],
-		defaultVersion: 1.2,
+		version: [1, 1.1, 1.2, 1.3],
+		defaultVersion: 1.3,
 		description: 'Language Model Anthropic',
 		defaults: {
 			name: 'Anthropic Chat Model',
@@ -135,7 +144,43 @@ export class LmChatAnthropic implements INodeType {
 				),
 				displayOptions: {
 					show: {
-						'@version': [{ _cnd: { gte: 1.2 } }],
+						'@version': [{ _cnd: { lte: 1.2 } }],
+					},
+				},
+			},
+			{
+				displayName: 'Model',
+				name: 'model',
+				type: 'resourceLocator',
+				default: {
+					mode: 'list',
+					value: 'claude-3-7-sonnet-20250219',
+					cachedResultName: 'Claude 3.7 Sonnet',
+				},
+				required: true,
+				modes: [
+					{
+						displayName: 'From List',
+						name: 'list',
+						type: 'list',
+						placeholder: 'Select a model...',
+						typeOptions: {
+							searchListMethod: 'searchModels',
+							searchable: true,
+						},
+					},
+					{
+						displayName: 'ID',
+						name: 'id',
+						type: 'string',
+						placeholder: 'Claude Sonnet',
+					},
+				],
+				description:
+					'The model. Choose from the list, or specify an ID. <a href="https://docs.anthropic.com/claude/docs/models-overview">Learn more</a>.',
+				displayOptions: {
+					show: {
+						'@version': [{ _cnd: { gte: 1.3 } }],
 					},
 				},
 			},
@@ -150,7 +195,7 @@ export class LmChatAnthropic implements INodeType {
 					{
 						displayName: 'Maximum Number of Tokens',
 						name: 'maxTokensToSample',
-						default: 4096,
+						default: DEFAULT_MAX_TOKENS,
 						description: 'The maximum number of tokens to generate in the completion',
 						type: 'number',
 					},
@@ -162,6 +207,11 @@ export class LmChatAnthropic implements INodeType {
 						description:
 							'Controls randomness: Lowering results in less random completions. As the temperature approaches zero, the model will become deterministic and repetitive.',
 						type: 'number',
+						displayOptions: {
+							hide: {
+								thinking: [true],
+							},
+						},
 					},
 					{
 						displayName: 'Top K',
@@ -171,6 +221,11 @@ export class LmChatAnthropic implements INodeType {
 						description:
 							'Used to remove "long tail" low probability responses. Defaults to -1, which disables it.',
 						type: 'number',
+						displayOptions: {
+							hide: {
+								thinking: [true],
+							},
+						},
 					},
 					{
 						displayName: 'Top P',
@@ -180,6 +235,30 @@ export class LmChatAnthropic implements INodeType {
 						description:
 							'Controls diversity via nucleus sampling: 0.5 means half of all likelihood-weighted options are considered. We generally recommend altering this or temperature but not both.',
 						type: 'number',
+						displayOptions: {
+							hide: {
+								thinking: [true],
+							},
+						},
+					},
+					{
+						displayName: 'Enable Thinking',
+						name: 'thinking',
+						type: 'boolean',
+						default: false,
+						description: 'Whether to enable thinking mode for the model',
+					},
+					{
+						displayName: 'Thinking Budget (Tokens)',
+						name: 'thinkingBudget',
+						type: 'number',
+						default: MIN_THINKING_BUDGET,
+						description: 'The maximum number of tokens to use for thinking',
+						displayOptions: {
+							show: {
+								thinking: [true],
+							},
+						},
 					},
 				],
 			},
@@ -189,13 +268,21 @@ export class LmChatAnthropic implements INodeType {
 	async supplyData(this: ISupplyDataFunctions, itemIndex: number): Promise<SupplyData> {
 		const credentials = await this.getCredentials('anthropicApi');
 
-		const modelName = this.getNodeParameter('model', itemIndex) as string;
+		const version = this.getNode().typeVersion;
+		const modelName =
+			version >= 1.3
+				? (this.getNodeParameter('model.value', itemIndex) as string)
+				: (this.getNodeParameter('model', itemIndex) as string);
+
 		const options = this.getNodeParameter('options', itemIndex, {}) as {
 			maxTokensToSample?: number;
 			temperature: number;
-			topK: number;
-			topP: number;
+			topK?: number;
+			topP?: number;
+			thinking?: boolean;
+			thinkingBudget?: number;
 		};
+		let invocationKwargs = {};
 
 		const tokensUsageParser = (llmOutput: LLMResult['llmOutput']) => {
 			const usage = (llmOutput?.usage as { input_tokens: number; output_tokens: number }) ?? {
@@ -208,6 +295,27 @@ export class LmChatAnthropic implements INodeType {
 				totalTokens: usage.input_tokens + usage.output_tokens,
 			};
 		};
+
+		if (options.thinking) {
+			invocationKwargs = {
+				thinking: {
+					type: 'enabled',
+					// If thinking is enabled, we need to set a budget.
+					// We fallback to 1024 as that is the minimum
+					budget_tokens: options.thinkingBudget ?? MIN_THINKING_BUDGET,
+				},
+				// The default Langchain max_tokens is -1 (no limit) but Anthropic requires a number
+				// higher than budget_tokens
+				max_tokens: options.maxTokensToSample ?? DEFAULT_MAX_TOKENS,
+				// These need to be unset when thinking is enabled.
+				// Because the invocationKwargs will override the model options
+				// we can pass options to the model and then override them here
+				top_k: undefined,
+				top_p: undefined,
+				temperature: undefined,
+			};
+		}
+
 		const model = new ChatAnthropic({
 			anthropicApiKey: credentials.apiKey as string,
 			modelName,
@@ -217,6 +325,7 @@ export class LmChatAnthropic implements INodeType {
 			topP: options.topP,
 			callbacks: [new N8nLlmTracing(this, { tokensUsageParser })],
 			onFailedAttempt: makeN8nLlmFailedAttemptHandler(this),
+			invocationKwargs,
 		});
 
 		return {